The sound made by a vehicle's door when closing is a characteristic often identified by consumers with the quality of the vehicle's construction. It is particularly appealing to potential new vehicle purchasers, and, not surprisingly, particularly important to vehicle manufacturers, that the vehicle doors make a solid and secure sound when they are shut. This sound is dependent, in large part, on the nature and quality of the door latch and striker designs and the interaction between the two parts. A hollow or tinny sound full of vibrations and reverberations is undesirable and a solid, vibration-free sound is preferred.
Various safety requirements, including those set by governmental agencies and vehicle manufacturers, dictate that striker bolts and door latching systems resist opening in the event of a crash or other mishap so as to protect the occupants of the vehicle from injury. In fact, out of an extraordinary concern for safety, vehicle manufacturers typically set safety requirements more stringent than those which are governmentally imposed.
Automobiles and other vehicles are generally equipped with a latch in the end of each door that engages a striker secured to the vehicle body pillar at the edge of the door opening. The latch in the door typically includes a slot that opens toward the vehicle interior and extends through a cutout in the face plate of the door. This slot guides the latch over the striker as the vehicle door is closed. As the latch moves over the striker, a pivotally mounted fork bolt that is part of the latching mechanism "strikes" and engages the striker. The striker causes the fork bolt to rotate to a latched position wherein the fork bolt engages the striker to hold the door closed. The fork bolt is held in the latched position until it is released by actuation of a door handle or other mechanism.
Examples of existing door latch mechanisms are disclosed, for example, in U.S. Pat. Nos. 4,130,308 to Jeavons; 5,000,495 to Wolfgang et al.; 5,520,426 to Arabia Jr. et al.; 5,348,357 to Konchan et al.; and 5,632,517 to Paulik et al. These door latches secure the vehicle door to the door frame by engagement with a door latch striker attached to the vehicle frame. Existing door latch strikers generally have a bolt or projection that is riveted to a base or bracket that secures the striker to the door pillar. Examples of such designs are disclosed in a number of U.S. patents including U.S. Pat. Nos. 4,941,696 to Yamada et al.; 4,998,759 to Peterson et al.; 5,050,917 to Hamada et al.; 5,209,531 to Thau; and 5,707,092 to Van Slembrouck et al. Each of these designs and many other conventional designs suffer from several limitations and drawbacks, most notably, a weak rivet connection which cannot effectively meet the vehicle manufacturers' more stringent safety standards for securing vehicle doors in the closed position. The use of a rivet connection limits the ability to use high strength or heat treated materials for the striker bolt and the base or mounting plate. Thus, a major cause of failure of the door latching mechanism in vehicles is the failure of the striker bolt itself or failure of the rivet connection between the striker bolt and the mounting plate. Also, these striker bolt designs do not result in the preferred solid, reverberation-free closing sound that is sought by vehicle consumers and manufacturers.
Conventionally, strikers have almost exclusively been made entirely of metal. This results in an unpleasant sounding metallic impact and friction when engaging with door latches, and may cause uneven contact with a latch or a guide piece and/or may cause play in the engagement between the striker and the door latch after excessive wear. These occurrences impair durability as a result of wear and breakage and may cause annoying or unappealing noises. There have been several attempts made to solve the problems existing in conventional strikers, some of which include the use of plastic or other polymeric or elastomeric material. However, as explained in further detail below, each of these attempts has some drawbacks and does not fully satisfy the needs of vehicle manufacturers.
U.S. Pat. Nos. 4,466,645 to Kobayashi and 4,981,313 to Makamura disclose the use of a plastic material overmolded over a conventional U-shaped, riveted striker assembly. The objective of providing the plastic overmolding is better noise reduction when the door latch engages the striker. However, such designs are subject to excessive wear at the point where the latch mechanism engages the striker. After repeated engagements, the plastic coating may be so fully worn at the impact point that the metal latching mechanism impacts the metal bolt causing the problems outlined above.
U.S. Pat. No. 5,215,342 to Yuge et al. discloses generally a striker with a plastic cover. The striker includes a base plate; a plastic overmolded, generally U-shaped rod riveted to the base plate; and a molded plastic cover sized to cover a major surface of the base plate to provide an attractive appearance. The cover has an elongate slit which is constructed to permit the U-shaped rod to pass therethrough and the cover includes two circular openings sized as to make a latched engagement when the plastic cover is properly attached to the base plate. This striker assembly also suffers from the deficiencies described above with respect to the assemblies disclosed in U.S. Pat. Nos. 4,466,645 and 4,981,313. Additionally, the engagement of the plastic cover requires an additional step in the automobile assembly process.
A more recent striker design, shown in FIG. 1 and identified generally as A, includes a plate B and a bolt C. The plate B is stamped into a generally U-shaped piece having striker bolt holes D and E and mounting bolt holes F therethrough. The striker bolt C slides through striker bolt hole D and is riveted in place through striker bolt hole E to close the U-shape of the plate B. The striker A is affixed to the door frame through the mounting bolt holes F. This design suffers from several of the limitations described above, e.g., the riveting of the striker bolt cannot meet strength objectives and the metal on metal impact and friction causes an undesirable closing sound and may lead to play in the engagement between the striker and door latch after excessive wear. The use of a smooth-bore extruded plastic sleeve around the bolt C is similar to the overmolded designs discussed above. Such a sleeve does not absorb a significant amount of impact energy and, if the sleeve is tightly fitted around the bolt so that it is not free to rotate, the sleeve is prone to wear after repeated strikings by the latch in the same place.
Accordingly, a need exists for a vehicle door striker that is capable of meeting or exceeding manufacturer safety requirements for door latches, has an attractive appearance, is cost effective to manufacture and install on the automobile, and makes the solid, reverberation-free closing sound that is appealing to vehicle consumers and manufacturers.